TWI658129B - Liquid crystal composition and use thereof, and liquid crystal display element - Google Patents

Abstract

The invention is a liquid crystal composition and a liquid crystal display element containing the composition. The liquid crystal composition contains a specific compound having a large positive dielectric anisotropy as a first component and a specific compound having a small viscosity as a first component. The second component may also contain a specific compound having a high upper temperature or a small viscosity as the third component, a specific compound having a large positive dielectric anisotropy as the fourth component, or a negative dielectric anisotropy A specific compound is used as the fifth component, and the liquid crystal composition has a nematic phase.

Description

Liquid crystal composition and use thereof, and liquid crystal display element

The present invention relates to a liquid crystal composition, a liquid crystal display element containing the composition, and the like. In particular, it relates to a liquid crystal composition having a positive dielectric anisotropy, and a twisted nematic (TN), optically compensated bend (OCB), and in-plane containing the composition. Active matrix (AM) elements in switching (IPS), fringe field switching (FFS), or field-induced photo-reactive alignment (FPA) modes.

In liquid crystal display elements, the operating mode based on liquid crystal molecules is classified as: phase change (PC), twisted nematic (TN), super twisted nematic (STN), Electrically controlled birefringence (ECB), optically compensated bend (OCB), in-plane switching (IPS), vertical alignment (VA), fringe field cut (Fringe Field Switching (FFS), field-induced photo-reactive alignment (FPA) and other modes. The component-based driving methods are classified into a passive matrix (PM) and an active matrix (AM). PM is classified into static and multiplex, etc. AM is classified into thin film transistor (TFT), metal-insulator-metal (MIM), and the like. TFTs are classified into amorphous silicon and polycrystal silicon. The latter is classified into a high temperature type and a low temperature type according to manufacturing steps. The classification based on the light source is a reflection type using natural light, a transmission type using backlight, and a semi-transmission type using both natural light and backlight.

The liquid crystal display element contains a liquid crystal composition having a nematic phase. This composition has appropriate characteristics. By improving the characteristics of the composition, an AM device having good characteristics can be obtained. The correlation between the characteristics of the two is summarized in Table 1 below. The characteristics of the composition will be further described based on a commercially available AM device. The temperature range of the nematic phase is related to the temperature range in which the element can be used. A preferred upper limit temperature of the nematic phase is about 70 ° C or higher, and a preferred lower limit temperature of the nematic phase is about -10 ° C or lower. The viscosity of a composition is related to the response time of the element. In order to display a moving image with a component, it is preferable that the response time is short. Ideally a response time shorter than 1 millisecond. Therefore, the viscosity of the composition is preferably small. More preferably, the viscosity is low at low temperatures. The elastic constant of the composition is related to the contrast of the device. In the device, in order to improve the contrast, it is more preferable that the composition has a large elastic constant.

The optical anisotropy of the composition is related to the contrast ratio of the element. Depending on the mode of the element, a large optical anisotropy or a small optical anisotropy is required, that is, an appropriate optical anisotropy. The product (Δn × d) of the optical anisotropy (Δn) of the composition and the cell gap (d) of the element is designed to maximize the contrast ratio. The appropriate product value depends on the type of operation mode. In a device having a mode such as TN, a suitable value is about 0.45 μm. In this case, a composition having a large optical anisotropy is preferred for a device having a small cell gap. The large dielectric anisotropy in the composition contributes to a low threshold voltage, a small power consumption, and a large contrast ratio in the device. Therefore, a large dielectric anisotropy is preferred. A large specific resistance in the composition contributes to a large voltage holding ratio and a large contrast ratio in the device. Therefore, a composition having a large specific resistance not only at room temperature but also at a temperature close to the upper limit temperature of the nematic phase in the initial stage is preferred. A composition having a large specific resistance not only at room temperature but also at a temperature close to the upper limit temperature of the nematic phase after long-term use is preferred. The stability of the composition to ultraviolet rays and heat is related to the life of the liquid crystal display element Link. When the stability is high, the life of the element is long. The characteristics described above are preferable for AM elements used in liquid crystal projectors, liquid crystal televisions, and the like.

A composition having a positive dielectric anisotropy is used for an AM device having a TN mode. A composition having a negative dielectric anisotropy is used for an AM device having a VA mode. For an AM device having the IPS mode or the FFS mode, a composition having a positive or negative dielectric anisotropy is used. A polymer sustained alignment (PSA) type AM device uses a composition having a positive or negative dielectric anisotropy. Examples of the liquid crystal composition having positive dielectric anisotropy are disclosed in Patent Documents 1 to 3 below.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 7-2832

[Patent Document 2] Japanese Patent Laid-Open No. 10-81679

[Patent Document 3] Japanese Patent Laid-Open No. 2008-69153

One object of the present invention is a liquid crystal composition having a high upper limit temperature of a nematic phase, a low lower limit temperature of a nematic phase, a small viscosity, an appropriate optical anisotropy, a large dielectric anisotropy, Among the characteristics such as specific resistance, high stability to ultraviolet light, high stability to heat, and large elastic constant, at least one characteristic is satisfied. Another object is a liquid crystal composition having a suitable balance between at least two characteristics. Another object is a liquid crystal display element containing such a composition. Another purpose It is an AM device with characteristics such as short response time, large voltage holding ratio, low threshold voltage, large contrast ratio, and long life.

The present invention is a liquid crystal composition containing at least one compound selected from the group of compounds represented by formula (1) as a first component, and a liquid crystal display element containing the composition. At least one compound from the group of compounds represented by formula (2) is a second component and has a nematic phase.

In formulas (1) and (2), R ¹ is an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, or an alkenyl group having 2 to 12 carbons; R ² is 1 to 12 carbons Alkyl group 3 or at least 1 hydrogen substituted by alkyl group having 1 to 12 carbon atoms; R ³ is hydrogen or 1 to 5 carbon group; ring A and ring B are independently 1,4-end Cyclohexyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene Phenyl, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5-diyl; Z ¹ and Z ^{2 are} independently a single bond , Ethylidene, vinylidene, methyleneoxy, carbonyloxy, or difluoromethyleneoxy; X ¹ is hydrogen or fluorine; Y ¹ is fluorine, chlorine, and at least one hydrogen is replaced by halogen An alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms having at least one hydrogen substituted with halogen, or an alkenyl group having 2 to 12 carbon atoms having at least one hydrogen substituted with halogen; j And k are independently 0, 1, 2 or 3; and the sum of j and k is 4 or less.

The invention has the advantages of a liquid crystal composition, which has a high upper limit temperature of the nematic phase, a low lower limit temperature of the nematic phase, a small viscosity, an appropriate optical anisotropy, a large dielectric anisotropy, and a large ratio Among the characteristics such as resistance, high stability to ultraviolet light, high stability to heat, and large elastic constant, at least one characteristic is satisfied. Another advantage is a liquid crystal composition having a suitable balance between at least two characteristics. Another advantage is a liquid crystal display element containing such a composition. Still another advantage is an AM element having characteristics such as short response time, large voltage holding ratio, low threshold voltage, large contrast ratio, long lifetime, and the like.

The terms used in this specification are described below. The terms "liquid crystal composition" and "liquid crystal display element" may be simply referred to as "composition" and "element", respectively. "Liquid crystal display device" is a generic term for a liquid crystal display panel and a liquid crystal display module. A "liquid crystal compound" is a compound having a liquid crystal phase such as a nematic phase and a smectic phase, and a liquid crystal compound that does not have a liquid crystal phase, but is used to adjust the temperature range, viscosity, and dielectric anisotropy of the nematic phase Class properties are mixed in for the purpose of A general term for compounds in the substance. The compound has a six-membered ring such as 1,4-cyclohexyl or 1,4-phenylene, and its molecular structure is rod-like. The "polymerizable compound" is a compound added for the purpose of forming a polymer in the composition. At least one compound selected from the group of compounds represented by formula (1) may be simply referred to as "compound (1)". "Compound (1)" means one compound or two or more compounds represented by formula (1). The same applies to compounds represented by other formulas. The "at least one" associated with "replaced" means that not only the position can be selected without limitation, but also the number of positions can be selected without limitation.

The liquid crystal composition is prepared by mixing a plurality of liquid crystal compounds. The ratio (content) of the liquid crystal compound is represented by a weight percentage (% by weight) based on the weight of the liquid crystal composition. To this composition, additives such as an optically active compound, an antioxidant, an ultraviolet absorber, a pigment, an antifoaming agent, a polymerizable compound, a polymerization initiator, and a polymerization inhibitor are added as needed. The ratio (addition amount) of the additive is the same as the ratio of the liquid crystal compound, and is represented by a weight percentage (% by weight) based on the weight of the liquid crystal composition. Sometimes parts per million by weight (ppm) is also used. The ratio of the polymerization initiator and the polymerization inhibitor is exceptionally expressed based on the weight of the polymerizable compound.

The "upper limit temperature of the nematic phase" may be simply referred to as the "upper limit temperature". The "lower limit temperature of the nematic phase" may be simply referred to as the "lower limit temperature". "High specific resistance" means that the composition has a large specific resistance not only at room temperature in the initial stage but also at a temperature close to the upper limit temperature of the nematic phase, and not only at room temperature after long-term use And has a large ratio at temperatures close to the upper limit of the nematic phase resistance. "Large voltage retention" means that the element has a large voltage retention not only at room temperature in the initial stage but also at a temperature close to the upper limit temperature of the nematic phase, and not only at room temperature after long-term use It also has a large voltage holding ratio at a temperature close to the upper limit temperature of the nematic phase.

The expression "at least one 'A' may be replaced by 'B'" means that the number of 'A' is arbitrary. When the number of 'A' is one, the position of 'A' is arbitrary, and when the number of 'A' is two or more, their positions can also be selected without restriction. This rule also applies to the expression "at least 1 'A' replaced by 'B'".

In the chemical formula of the component compound, the symbol of the terminal group R ¹ is used for various compounds. In these compounds, the two groups represented by arbitrary two R ¹ may be the same or different. For example, there may be a case where R ¹ of the compound (1) is an ethyl group and R ¹ of the compound (1-1) is an ethyl group. In some cases, R ¹ of the compound (1) is an ethyl group, and R ¹ of the compound (1-1) is a propyl group. This rule also applies to symbols such as R ⁴ and X ¹ . In formula (1), when j is 2, there are two rings A. In this compound, the two rings represented by the two rings A may be the same or different. When j is greater than 2, this rule also applies to any two rings A. This rule also applies to Z ¹ , ring B, and so on.

2-Fluoro-1,4-phenylene refers to the two divalent groups described below. In the chemical formula, fluorine may be leftward (L) or rightward (R). This rule also applies to divalent radicals of asymmetric rings such as tetrahydropyran-2,5-diyl.

The present invention includes the following items.

Item 1. A liquid crystal composition comprising, as a first component, at least one compound selected from the group of compounds represented by formula (1), and a liquid crystal composition selected from the group of compounds represented by formula (2). At least one compound as the second component and has a nematic phase,

In formulas (1) and (2), R ¹ is an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, or an alkenyl group having 2 to 12 carbons; R ² is 1 to 12 carbons Alkyl group 3 or at least 1 hydrogen substituted by alkyl group having 1 to 12 carbon atoms; R ³ is hydrogen or 1 to 5 carbon group; ring A and ring B are independently 1,4-end Cyclohexyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene Phenyl, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5-diyl; Z ¹ and Z ^{2 are} independently a single bond , Ethylidene, vinylidene, methyleneoxy, carbonyloxy, or difluoromethyleneoxy; X ¹ is hydrogen or fluorine; Y ¹ is fluorine, chlorine, and at least one hydrogen is replaced by halogen An alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms having at least one hydrogen substituted with halogen, or an alkenyl group having 2 to 12 carbon atoms having at least one hydrogen substituted with halogen; j And k are independently 0, 1, 2 or 3; and the sum of j and k is 4 or less.

Item 2. The liquid crystal composition according to Item 1, which contains, as a first component, at least one compound selected from the group consisting of compounds represented by formula (1-1) to formula (1-12),

In the formulae (1-1) to (1-12), R ¹ is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms; X ¹ , X ² , X ³ , X ⁴ , X ⁵ , X ^6, and X ^{7 are} independently hydrogen or fluorine; Y ¹ is fluorine, chlorine, at least one hydrogen is substituted with a halogen-containing alkyl group having 1 to 12 carbon atoms, at least An alkoxy group having 1 to 12 carbon atoms substituted by halogen with one hydrogen, or an alkoxy group having 2 to 12 carbon atoms substituted with at least one hydrogen substituted with halogen.

Item 3. The liquid crystal composition according to Item 1 or 2, wherein the ratio of the first component is in a range of 5 to 40% by weight and the ratio of the second component is 10 to 10% by weight based on the weight of the liquid crystal composition. A range of 60% by weight.

Item 4. The liquid crystal composition according to any one of Items 1 to 3, further comprising, as a third component, at least one compound selected from the group of compounds represented by formula (3),

In formula (3), R ⁴ and R ^{5 are} independently an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and at least one hydrogen is substituted with halogen Alkyl group having 1 to 12 carbon atoms, or alkenyl group having 2 to 12 carbon atoms in which at least one hydrogen is replaced by fluorine; ring C and ring D are independently 1,4-cyclohexyl, 1,4-cyclo Phenyl, 2-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene; Z ³ is a single bond, ethylidene, or carbonyloxy; n is 1, 2 Or 3; here, when n is 1, ring D is 1,4-phenylene.

Item 5. The liquid crystal composition according to any one of Items 1 to 4, which contains at least one compound selected from the group consisting of compounds represented by Formula (3-1) to Formula (3-12) As a third component,

In the formulae (3-1) to (3-12), R ⁴ and R ^{5 are} independently an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an alkenyl group having 2 to 12 carbon atoms. Or an alkenyl group having 2 to 12 carbons in which at least one hydrogen is replaced with fluorine.

Item 6. The liquid crystal composition according to item 4 or item 5, wherein the proportion of the third component is in a range of 5 to 55% by weight based on the weight of the liquid crystal composition.

Item 7. The liquid crystal composition according to any one of Items 1 to 6, further comprising, as a fourth component, at least one compound selected from the group of compounds represented by formula (4),

In formula (4), R ⁶ is an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, or an alkenyl group having 2 to 12 carbons; ring E is 1,4-cyclohexyl, 1 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyrimidine -2,5-diyl, or tetrahydropyran-2,5-diyl; Z ⁴ is a single bond, ethylene, carbonyloxy, or difluoromethyleneoxy; X ⁸ and X ^{9 are} independent Ground is hydrogen or fluorine; Y ² is fluorine, chlorine, at least one hydrogen alkyl group having 1 to 12 carbon atoms substituted with halogen, at least one hydrogen substituted alkyl group with 1 to 12 carbon atoms halogen, Or an alkenyl group having 2 to 12 carbons with at least one hydrogen substituted with halogen; p is 1, 2, 3, or 4.

Item 8. The liquid crystal composition according to any one of Items 1 to 7, which contains at least one compound selected from the group consisting of compounds represented by formula (4-1) to formula (4-24) As a fourth component,

In the formulae (4-1) to (4-24), R ⁶ is an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, or an alkenyl group having 2 to 12 carbons.

Item 9. The liquid crystal composition according to item 7 or item 8, wherein the proportion of the fourth component is in the range of 5% to 35% by weight based on the weight of the liquid crystal composition.

Item 10. The liquid crystal composition according to any one of Items 1 to 9, which contains, as a fifth component, at least one compound selected from the group of compounds represented by formula (5),

In formula (5), R ⁷ and R ^{8 are} independently an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and an alkenyl group having 2 to 12 carbon atoms. Or at least one hydrogen substituted alkyl group having 1 to 12 carbon atoms; ring F and ring I are independently 1,4-cyclohexyl, 1,4-cyclohexenyl (1,4 -cyclohexenylene), 1,4-phenylene, 1,4-phenylene with at least one hydrogen substituted by fluorine or chlorine, or tetrahydropyran-2,5-diyl; ring G is 2,3 -Difluoro-1,4-phenylene, 2-chloro-3-fluoro-1,4-phenylene, 2,3-difluoro-5-methyl-1,4-phenylene, 3, 4,5-trifluoronaphthalene-2,6-diyl, or 7,8-difluorochromane-2,6-diyl (7,8-difluorochromane-2,6-diyl); Z ⁵ and Z ^{6 is} independently a single bond, an ethylidene group, a carbonyloxy group, or a methyleneoxy group; e is 1, 2 or 3; f is 0 or 1; and the sum of e and f is 3 or less.

Item 11. The liquid crystal composition according to any one of Items 1 to 10, which contains at least one compound selected from the group consisting of compounds represented by Formula (5-1) to Formula (5-19) As the fifth component,

In the formulae (5-1) to (5-19), R ⁷ and R ^{8 are} independently an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an alkenyl group having 2 to 12 carbon atoms. , An alkenyloxy group having 2 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is replaced with halogen.

Item 12. The liquid crystal composition according to item 10 or item 11, wherein the proportion of the fifth component is in a range of 3% by weight to 25% by weight based on the weight of the liquid crystal composition.

Item 13. The liquid crystal composition according to any one of Items 1 to 12, wherein the upper limit temperature of the nematic phase is 70 ° C. or higher, and the optical anisotropy (measured at 25 ° C.) at a wavelength of 589 nm is 0.07 or higher. The dielectric anisotropy (measured at 25 ° C) at a frequency of 1 kHz is 2 or more.

Item 14. A liquid crystal display element comprising the liquid crystal composition according to any one of Items 1 to 13.

Item 15. The liquid crystal display element according to item 14, wherein the operation mode of the liquid crystal display element is TN mode, ECB mode, OCB mode, IPS mode, FFS mode, or FPA mode, and the driving mode of the liquid crystal display element is an active matrix method. .

Item 16. The use of the liquid crystal composition according to any one of Items 1 to 13, which is used in a liquid crystal display element.

The present invention also includes the following items. (a) The composition further contains at least one of additives such as an optically active compound, an antioxidant, an ultraviolet absorber, a pigment, an antifoaming agent, a polymerizable compound, a polymerization initiator, and a polymerization inhibitor. (b) An AM device containing the composition. (c) The composition further containing a polymerizable compound, and a polymer stable alignment (PSA) type AM device containing the composition. (d) A polymer stabilized alignment (PSA) type AM device containing the composition and polymerizing a polymerizable compound in the composition. (e) An element containing the composition and having a mode of PC, TN, STN, ECB, OCB, IPS, VA, FFS, or FPA. (f) a transmissive element containing The composition. (g) Use of the composition as a composition having a nematic phase. (h) Use as an optically active composition by adding an optically active compound to the composition.

The composition of the present invention will be described in the following order. First, the constitution of the component compounds in the composition will be described. Second, the main characteristics of the component compounds and the main effects of the compounds on the composition will be described. Third, the combination of components in the composition, the preferred ratio of the components, and the basis thereof will be described. Fourth, preferred embodiments of the component compounds will be described. Fifth, preferred component compounds are shown. Sixth, additives that can be added to the composition will be described. Seventh, a method for synthesizing the component compounds will be described. Finally, the use of the composition will be described.

First, the constitution of the component compounds in the composition will be described. The composition of the present invention is classified into a composition A and a composition B. The composition A contains a liquid crystal compound selected from the compound (1), the compound (2), the compound (3), the compound (4), and the compound (5), and may further contain other liquid crystal compounds and additives. Things. The "other liquid crystal compound" is a liquid crystal compound different from the compound (1), the compound (2), the compound (3), the compound (4), and the compound (5). Such a compound is mixed in the composition for the purpose of further adjusting the characteristics. The additives are optically active compounds, antioxidants, ultraviolet absorbers, pigments, defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, and the like.

Composition B contains substantially only a liquid crystal compound selected from the group consisting of compound (1), compound (2), compound (3), compound (4), and compound (5). "real By "qualitatively" it is meant that the composition may contain additives, but does not contain other liquid crystal compounds. Compared with composition A, the number of components of composition B is small. From the viewpoint of cost reduction, the composition B is superior to the composition A. From the viewpoint that the characteristics can be further adjusted by mixing other liquid crystal compounds, the composition A is superior to the composition B.

Second, the main characteristics of the component compounds and the main effects of the compounds on the characteristics of the composition will be described. Based on the effects of the present invention, the main characteristics of the component compounds are summarized in Table 2. In the symbols in Table 2, L is large or high, M is medium, and S is small or low. Symbols L, M, and S are classifications based on a qualitative comparison between component compounds, and 0 (zero) means that the value is zero, or close to zero.

When the component compounds are mixed in the composition, the main effects of the component compounds on the characteristics of the composition are as follows. The compound (1) improves the dielectric anisotropy. Compound (2) reduces viscosity. The compound (3) raises the upper limit temperature or lowers the lower limit temperature. The compound (4) lowers the lower limit temperature and increases the dielectric anisotropy. The compound (5) increases the dielectric constant in the minor axis direction.

Third, the combination of the components in the composition and the preferred ratio of the component compounds The example and its basis will be explained. The combination of the components in the composition is: the first component + the second component, the first component + the second component + the third component, the first component + the second component + the fourth component, the first component + the second component + the first component Three components + fourth component, first component + second component + fifth component, first component + second component + third component + fifth component, first component + second component + fourth component + fifth component Or the first component + the second component + the third component + the fourth component + the fifth component. A preferred combination of the components in the composition is a first component + a second component + a third component or a first component + a second component + a third component + a fourth component.

In order to improve the dielectric anisotropy, the preferred ratio of the first component is about 5 wt% or more. In order to lower the lower limit temperature or to reduce the viscosity, the preferred ratio of the first component is about 40 wt% or less. A particularly preferred ratio is in the range of about 5% to about 30% by weight. A particularly preferred ratio is in the range of about 5 wt% to about 25 wt%.

In order to reduce the viscosity, the preferred ratio of the second component is about 10% by weight or more. In order to improve the dielectric anisotropy, the preferred ratio of the second component is about 60% by weight or less. A particularly preferred ratio is in the range of about 15% by weight to about 55% by weight. A particularly preferred ratio is in the range of about 20% by weight to about 50% by weight.

In order to increase the upper limit temperature, or to reduce the viscosity, the preferred ratio of the third component is about 5% by weight or more, and to improve the dielectric anisotropy, the preferred ratio of the third component is about 55% by weight or less. A particularly preferred ratio is in the range of about 10% by weight to about 50% by weight. A particularly preferred ratio is in the range of about 15% by weight to about 45% by weight.

In order to improve the dielectric anisotropy, the preferred ratio of the fourth component is about 5% by weight or more. In order to lower the lower limit temperature, the preferred ratio of the fourth component is about 35% by weight. %the following. A particularly preferred ratio is in the range of about 5% to about 30% by weight. A particularly preferred ratio is in the range of about 5 wt% to about 25 wt%.

In order to improve the dielectric anisotropy, the preferred ratio of the fifth component is about 3% by weight or more. In order to lower the lower limit temperature, the preferred ratio of the fifth component is about 25% by weight or less. A particularly preferred ratio is in the range of about 5% to about 20% by weight. A particularly preferred ratio is in the range of about 5 wt% to about 15 wt%.

Fourth, preferred embodiments of the component compounds will be described. R ¹ and R ^{6 are} independently an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, or an alkenyl group having 2 to 12 carbons. In order to improve the stability to ultraviolet rays or heat, preferred R ¹ or R ⁶ is an alkyl group having 1 to 12 carbon atoms. R ² is an alkyl group having 1 to 3 carbons or an alkyl group having 1 to 12 carbons in which at least one hydrogen is replaced with halogen. Preferred R ² is propyl or 3-fluoropropyl. The three-dimensional configuration of -CH = CH- in -CH = CH-R ² includes a trans configuration and a cis configuration, and a trans configuration is preferred. R ³ is hydrogen or an alkyl group having 1 to 5 carbon atoms. Preferred R ³ is hydrogen or methyl. R ⁴ and R ^{5 are} independently an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, an alkenyl group having 2 to 12 carbons, and at least 1 hydrogen having 1 to 12 carbon atoms substituted with halogen Alkyl, or at least 1 hydrogen alkenyl having 2 to 12 carbon atoms substituted with fluorine. In order to improve the stability to ultraviolet rays or heat, etc., a preferred R ⁴ or R ⁵ is an alkyl group having 1 to 12 carbon atoms. In order to lower the lower limit temperature or to reduce viscosity, a preferred R ⁴ or R ⁵ is a carbon number. 2 to 12 alkenyl. R ⁷ and R ^{8 are} independently an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, an alkenyl group having 2 to 12 carbons, an alkenyl group having 2 to 12 carbons, or at least one Alkyl having 1 to 12 carbons substituted by hydrogen with halogen. In order to improve stability, preferred R ⁷ or R ⁸ is an alkyl group having 1 to 12 carbons, and in order to improve dielectric anisotropy, preferred R ⁷ or R ⁸ is an alkoxy group having 1 to 12 carbons. The preferred halogen is fluorine or chlorine, and the more preferred halogen is fluorine.

Preferred alkyl groups are: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, or octyl. To reduce viscosity, particularly preferred alkyl groups are ethyl, propyl, butyl, pentyl, or heptyl.

Preferred alkoxy groups are: methoxy, ethoxy, propoxy, butoxy, pentoxy, hexyloxy, or heptyloxy. To reduce viscosity, a particularly preferred alkoxy group is methoxy or ethoxy.

Preferred alkenyls are: vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, or 5-hexenyl. To reduce viscosity, particularly preferred alkenyl is vinyl, 1-propenyl, 3-butenyl or 3-pentenyl. The preferred stereo configuration of -CH = CH- in these alkenyl groups depends on the position of the double bond. For reasons such as reducing viscosity, it compares with alkenyl groups such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl, 3-pentenyl, and 3-hexenyl. It is preferably a trans configuration. Among alkenyl groups such as 2-butenyl, 2-pentenyl, and 2-hexenyl, the cis configuration is preferred. Among these alkenyl groups, linear alkenyl groups are superior to branched alkenyl groups.

Preferred examples of alkenyl in which at least one hydrogen is replaced by fluorine are: 2,2-difluorovinyl, 3,3-difluoro-2-propenyl, 4,4-difluoro-3-butenyl , 5,5-difluoro-4-pentenyl, or 6,6-difluoro-5-hexenyl. In order to reduce the viscosity, a particularly preferred example is 2,2-difluorovinyl or 4,4-difluoro-3-butenyl.

j and k are independently 0, 1, 2 or 3, and the sum of j and k is 4 or less. In order to lower the lower limit temperature, preferably j is 0. In order to increase the upper limit temperature, k is preferably 1 or 2. n is 1, 2 or 3. In order to lower the lower limit temperature, the preferred n is two. p is 1, 2, 3, or 4. In order to lower the lower limit temperature, a preferred p is 2 and in order to increase the dielectric anisotropy, a preferred p is 3. e is 1, 2 or 3, f is 0 or 1, and the sum of e and f is 3 or less. In order to reduce the viscosity, the preferred e is 1, and in order to increase the upper limit temperature, the preferred e is 2 or 3. In order to reduce the viscosity, the preferred f is 0, and to lower the lower limit temperature, the preferred f is 1.

Z ¹ and Z ^{2 are} independently a single bond, ethylene, vinylene, methyleneoxy, carbonyloxy, or difluoromethyleneoxy. In order to reduce the viscosity, the preferred Z ¹ or Z ² is a single bond. In order to improve the dielectric anisotropy, the preferred Z ¹ or Z ² is a difluoromethyleneoxy group. Z ³ is a single bond, ethylene or carbonyloxy. To reduce viscosity, the preferred Z ³ is a single bond. Z ⁴ is a single bond, ethylene, carbonyloxy, or difluoromethyleneoxy. To increase the dielectric anisotropy, the preferred Z ⁴ is difluoromethyleneoxy. Z ⁵ and Z ^{6 are} independently a single bond, ethylene, carbonyloxy, or methyleneoxy. In order to reduce the viscosity, the preferred Z ⁵ or Z ⁶ is a single bond. In order to improve the dielectric anisotropy, the preferred Z ⁵ or Z ⁶ is a methyleneoxy group.

Ring A and Ring B are independently 1,4-cyclohexyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene , 2,6-difluoro-1,4-phenylene, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5- Second base. In order to improve optical anisotropy, the preferred ring A or ring B is 1,4-phenylene or 2-fluoro-1,4-phenylene. Ring C and Ring D are independently 1,4-cyclohexyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene When n is 1, ring D is 1,4-phenylene. In order to reduce the viscosity, the preferred ring C or ring D is 1,4-cyclohexyl, or in order to improve the optical anisotropy, the preferred ring C or ring D is 1,4-phenylene. Ring E is 1,4-cyclohexyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6- Difluoro-1,4-phenylene, pyrimidine-2,5-diyl, or tetrahydropyran-2,5-diyl. To improve optical anisotropy, the preferred ring E is 1,4-phenylene or 2-fluoro-1,4-phenylene. Ring F and Ring I are independently 1,4-cyclohexyl, 1,4-cyclohexenyl, 1,4-phenyl, at least one hydrogen substituted by fluorine or chlorine Phenyl, or tetrahydropyran-2,5-diyl. Preferred examples of "at least one hydrogen substituted by 1,4-phenylene with fluorine or chlorine" are 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene Or 2-chloro-3-fluoro-1,4-phenylene. In order to reduce the viscosity, the preferred ring F or ring I is 1,4-cyclohexyl. In order to improve the dielectric anisotropy, the preferred ring F or ring I is tetrahydropyran-2,5-diyl. In order to improve optical anisotropy, the preferred ring F or ring I is 1,4-phenylene. Ring G is 2,3-difluoro-1,4-phenylene, 2-chloro-3-fluoro-1,4-phenylene, 2,3-difluoro-5-methyl-1,4- Phenylene, 3,4,5-trifluoronaphthalene-2,6-diyl, or 7,8-difluorochromogen-2,6-diyl. To increase the dielectric anisotropy, the preferred ring G is 2,3-difluoro-1,4-phenylene. In order to increase the upper limit temperature, the stereo configuration related to 1,4-cyclohexyl is a trans configuration rather than a cis configuration. Tetrahydropyran-2,5-diyl is or , Preferably .

X ¹ , X ² , X ³ , X ⁴ , X ⁵ , X ⁶ , X ⁷ , X ⁸ and X ^{9 are} independently hydrogen or fluorine. In order to improve the dielectric anisotropy, preferred X ¹ , X ² , X ³ , X ⁴ , X ⁵ , X ⁶ , X ⁷ , X ⁸ or X ⁹ are fluorine.

Y ¹ and Y ^{2 are} independently fluorine, chlorine, an alkyl group having 1 to 12 carbons substituted by at least one hydrogen with halogen, an alkoxy group 1 to 12 carbon substituted with at least one hydrogen with halogen, or An alkenyl group having 2 to 12 carbon atoms in which at least one hydrogen is replaced with a halogen. In order to lower the lower limit temperature, preferred Y ¹ or Y ² is fluorine.

Fifth, preferred component compounds are shown. Preferred compound (1) is the compound (1-1) to compound (1-12) according to item 2. Among these compounds, it is preferred that at least one of the first components is compound (1-1), compound (1-2), compound (1-3), compound (1-4), compound (1-7) , Compound (1-8), compound (1-9), compound (1-10), or compound (1-12). It is preferable that at least two kinds of the first component are compound (1-3) and compound (1-4), compound (1-3) and compound (1-7), compound (1-4) and compound (1- 10), or a combination of compound (1-10) and compound (1-12).

Preferred compound (3) is the compound (3-1) to compound (3-12) according to item 5. Among these compounds, it is preferred that at least one of the third components is compound (3-2), compound (3-4), compound (3-5), compound (3-6), compound (3-9) Or compound (3-12). It is preferred that at least two of the third component be compound (3-2) and compound (3-4), compound (3-2) and compound (3-5), or compound (3-2) and compound (3 -6).

Preferred compound (4) is the compound (4-1) to compound (4-24) according to item 8. Of these compounds, it is preferred that at least one of the fourth components is a compound. (4-4), compound (4-9), compound (4-11), compound (4-12), compound (4-15), compound (4-16), compound (4-18), or compound (4-19). It is preferable that at least two kinds of the fourth component are compound (4-9) and compound (4-12), compound (4-9) and compound (4-18), compound (4-12) and compound (4- 15), compound (4-12) and compound (4-18), compound (4-15) and compound (4-18), or a combination of compound (4-18) and compound (4-19).

Preferred compound (5) is the compound (5-1) to compound (5-19) according to item 11. Among these compounds, it is preferable that at least one of the fifth component is the compound (5-1), the compound (5-3), the compound (5-4), the compound (5-6), and the compound (5-8). Or compound (5-13). Preferably, at least two of the fifth component are the compound (5-1) and the compound (5-6), the compound (5-1) and the compound (5-13), the compound (5-3) and the compound (5- 6), compound (5-3) and compound (5-13), compound (5-4) and compound (5-6), or a combination of compound (5-4) and compound (5-8).

Sixth, additives that can be added to the composition will be described. Such additives are optically active compounds, antioxidants, ultraviolet absorbers, pigments, defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, and the like. An optically active compound is added to the composition for the purpose of giving a torsion angle to the helical structure of the liquid crystal. Examples of such compounds are compound (6-1) to compound (6-5). A preferred ratio of the optically active compound is about 5 wt% or less. A particularly preferred ratio is in the range of about 0.01% by weight to about 2% by weight.

In order to prevent the decrease in specific resistance caused by heating in the atmosphere, or to maintain a large voltage holding ratio not only at room temperature, but also at a temperature close to the upper limit temperature, after using the element for a long time, antioxidants Added to the composition. Preferred examples of the antioxidant are a compound (7) and the like in which t is an integer of 1 to 9.

In compound (7), preferred t is 1, 3, 5, 7, or 9. A particularly preferred t is 7. The compound (7) with t of 7 is small in volatility, and is therefore effective for maintaining a large voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature after a long-term use of the device. In order to obtain the effect, a preferred ratio of the antioxidant is about 50 ppm or more, and in order not to lower the upper limit temperature, or not to raise the lower limit temperature, the preferred ratio of the antioxidant is about 600 ppm or less. A particularly preferred ratio is in the range of about 100 ppm to about 300 ppm.

Preferable examples of the ultraviolet absorber include benzophenone derivatives, benzoate derivatives, and triazole derivatives. In addition, a light stabilizer such as an amine having a steric hindrance is also preferable. In order to obtain the effect, the preferred ratio of these absorbers or stabilizers is about 50 ppm or more. In order not to lower the upper limit temperature, or to not raise the lower limit temperature, the preferred ratio of these absorbers or stabilizers is about 10,000 ppm or less . A particularly preferred ratio is in the range of about 100 ppm to about 10,000 ppm.

A dichroic dye such as an azo-based pigment, an anthraquinone-based pigment, or the like is added to the composition in order to be suitable for an element in a guest host (GH) mode. A preferred ratio of the pigment is in the range of about 0.01% by weight to about 10% by weight. To prevent foaming, antifoaming agents such as dimethyl silicone oil and methylphenyl silicone oil are added to the composition. In order to obtain the effect, a preferred ratio of the defoaming agent is About 1 ppm or more. In order to prevent poor display, the preferred ratio of the antifoaming agent is about 1000 ppm or less. A particularly preferred ratio is in the range of about 1 ppm to about 500 ppm.

A polymerizable compound is added to the composition in order to be suitable for a polymer stable alignment (PSA) type device. Preferred examples of the polymerizable compound are acrylate, methacrylate, vinyl compound, vinyloxy compound, propenyl ether, and epoxy compound (oxirane, oxetane). Compounds having a polymerizable group such as, vinyl ketone, and the like. Particularly preferred examples are derivatives of acrylates or methacrylates. In order to obtain the above effect, a preferable ratio of the polymerizable compound is about 0.05% by weight or more. In order to prevent display failure, a preferable ratio of the polymerizable compound is about 10% by weight or less. A particularly preferred ratio is in the range of about 0.1% by weight to about 2% by weight. The polymerizable compound is polymerized by irradiation with ultraviolet rays. Polymerization may be performed in the presence of an initiator such as a photopolymerization initiator. Suitable conditions for carrying out the polymerization, suitable types of initiators, and suitable amounts are known to those skilled in the art and are described in the literature. For example, Irgacure 651 (registered trademark; BASF), Irgacure 184 (registered trademark; BASF), or Darocure 1173 (registered trademark; BASF) as photoinitiators ) Suitable for free radical polymerization. The preferred ratio of the photopolymerization initiator is in the range of about 0.1% by weight to about 5% by weight based on the weight of the polymerizable compound. A particularly preferred ratio is in the range of about 1% by weight to about 3% by weight.

When storing a polymerizable compound, a polymerization inhibitor may be added to prevent polymerization. The polymerizable compound is usually added to the composition without removing the polymerization inhibitor. Examples of polymerization inhibitors are hydroquinone, methyl para Hydroquinone derivatives such as methylhydroquinone, 4-tert-butylcatechol, 4-methoxyphenol, and phenothiazine ( phenothiazine), etc.

Seventh, a method for synthesizing the component compounds will be described. These compounds can be synthesized by known methods. Illustrative synthesis methods. Compound (1) is synthesized by a method described in Japanese Patent Laid-Open No. 10-81679. Compound (2) is synthesized by a method described in Japanese Patent Laid-Open No. 59-176221. Compound (3-12) is synthesized by the method described in Japanese Patent Laid-Open No. 2-237949. Compound (4-2) and compound (4-6) were synthesized by the method described in Japanese Patent Laid-Open No. 2-233626. The compound (5-1) and the compound (5-6) were synthesized by a method described in Japanese Patent Application Publication No. Hei 2-503441. Antioxidants are commercially available. The compound of formula (7) where t is 1 is available from Sigma-Aldrich Corporation. Compound (7) and the like where t is 7 are synthesized by a method described in US Pat. No. 3,660,505.

Finally, the use of the composition will be described. The composition of the present invention mainly has a lower limit temperature of about -10 ° C or lower, an upper limit temperature of about 70 ° C or higher, and optical anisotropy in a range of about 0.07 to about 0.20. The device containing this composition has a large voltage holding ratio. This composition is suitable for an AM device. This composition is particularly suitable for a transmissive AM device. It is also possible to prepare an optically anisotropic composition having a range of about 0.08 to about 0.25 by controlling the ratio of the component compounds or mixing other liquid crystal compounds, and further have an optical range of about 0.10 to about 0.30 Anisotropic composition. The composition can be used as a composition having a nematic phase, and It can be used as an optically active composition by adding an optically active compound.

This composition can be used for an AM device. It can also be used for PM devices. This composition can be used for AM devices and PM devices with PC, TN, STN, ECB, OCB, IPS, FFS, VA, FPA and other modes. Particularly preferred is for AM elements having a TN mode, an OCB mode, an IPS mode, or an FFS mode. In an AM device having an IPS mode or an FFS mode, when no voltage is applied, the arrangement of the liquid crystal molecules with respect to the glass substrate may be parallel or vertical. These devices can be reflective, transmissive, or transflective. It is preferably used for a transmissive element. It can also be used for amorphous silicon-TFT elements or polycrystalline silicon-TFT elements. It can also be used for nematic curvilinear aligned phase (NCAP) elements made by microencapsulating this composition, or polymer dispersed (polymer dispersed, three-dimensional network polymers) formed in the composition. PD) type element.

[Example]

The present invention will be further described in detail through examples. The invention is not limited by these examples. The synthesized compounds were identified by methods such as nuclear magnetic resonance (NMR) analysis. The properties of the compounds and compositions were measured by the methods described below.

NMR analysis: For measurement, DRX-500 manufactured by Bruker BioSpin was used. ^In the measurement of ¹ H-NMR, the sample was dissolved in a deuterated solvent such as CDCl ₃ and the measurement was performed at room temperature under the conditions of 500 MHz and a cumulative number of 16 times. Tetramethylsilane was used as the internal standard. ^{In the 19} F-NMR measurement, CFCl _{3 was} used as an internal standard, and the total number of measurements was performed 24 times. In the description of the nuclear magnetic resonance spectrum, s refers to singlet, d refers to doublet, t refers to triplet, q refers to quartet, and quin refers to quintet. (quintet), sex refers to a sextet, (sextet), m refers to a multiplet, and br refers to a broad peak.

Gas chromatography analysis: The measurement was performed using a GC-14B gas chromatograph manufactured by Shimadzu Corporation. The carrier gas was helium (2 mL / min). The sample gasification chamber was set to 280 ° C, and the detector (flame ionization detector (FID)) was set to 300 ° C. For separation of component compounds, a capillary column DB-1 (length 30 m, inner diameter 0.32 mm, film thickness 0.25 μm) manufactured by Agilent Technologies Inc. was used; the fixed liquid phase was dimethylpolysiloxane; Non-polar). After the column was held at 200 ° C for 2 minutes, the temperature was raised to 280 ° C at a rate of 5 ° C / min. After preparing a sample as an acetone solution (0.1% by weight), 1 μL of the sample was injected into the sample gasification chamber. The recorder is a C-R5A Chromatopac manufactured by Shimadzu Corporation or its equivalent. The obtained gas chromatogram shows the retention time of the peak corresponding to the component compounds and the area of the peak.

As a solvent for diluting the sample, chloroform, hexane, or the like can be used. To separate the component compounds, the following capillary columns can be used. HP-1 manufactured by Agilent Technologies Co., Ltd. (length 30m, inner diameter 0.32mm, film thickness 0.25μm), Rtx-1 manufactured by Restek Corporation (length 30m, inner diameter 0.32mm, film thickness 0.25μm ), BP-1 (length 30 m, inner diameter 0.32 mm, film thickness 0.25 μm) manufactured by SGE International Pty. Ltd. of Australia. To prevent the compound peaks from overlapping, a capillary column CBP1-M50-025 (length 50 m, inner diameter 0.25 mm, and film thickness 0.25 μm) manufactured by Shimadzu Corporation can be used.

The ratio of the liquid crystal compound contained in the composition can be calculated by the method described below. A gas chromatograph (FID) was used to detect a mixture of liquid crystal compounds. The area ratio of the peaks in the gas chromatogram corresponds to the ratio (weight ratio) of the liquid crystal compound. When the capillary column described above is used, the correction coefficient of various liquid crystal compounds can be regarded as one. Therefore, the ratio (% by weight) of the liquid crystalline compound can be calculated from the peak area ratio.

Measurement sample: When measuring the characteristics of a composition, the composition is directly used as a sample. When measuring the characteristics of a compound, a sample for measurement was prepared by mixing the compound (15% by weight) with a mother liquid crystal (85% by weight). From the values obtained by the measurement, the characteristic values of the compounds were calculated by extrapolation. (Extrapolated value) = {(measured value of sample) -0.85 × (measured value of mother liquid crystal)} / 0.15. When the smectic phase (or crystal) is precipitated at 25 ° C at this ratio, the ratio of the compound to the mother liquid crystal is 10% by weight: 90% by weight, 5% by weight: 95% by weight, and 1% by weight: 99% % Order change. This extrapolation method was used to determine the values of the compound-dependent upper temperature, optical anisotropy, viscosity, and dielectric anisotropy.

The following mother liquid crystals were used. The proportion of the component compounds is expressed in% by weight.

Measurement method: The characteristics were measured by the following method. These methods are mostly methods described in the JEITA standard (JEITA.ED-2521B) reviewed and formulated by the Japan Electronics and Information Technology Industries Association (hereinafter referred to as JEITA) or modified and modified.成 的 方法。 into the method. A thin film transistor (TFT) was not mounted on the TN device used for the measurement.

(1) Upper limit temperature (NI; ° C) of the nematic phase: A sample is placed on a hot plate of a melting point measuring device equipped with a polarizing microscope, and heated at a rate of 1 ° C / min. The temperature at which a part of the sample changed from a nematic phase to an isotropic liquid was measured.

(2) Lower limit temperature of nematic phase (T _C ; ℃): Put the sample with nematic phase into the glass bottle at 0 ℃, -10 ℃, -20 ℃, -30 ℃ and -40 ℃. After storing in a freezer for 10 days, the liquid crystal phase was observed. For example, when the sample is in the state of a nematic phase at -20 ° C and changes to a crystal or a smectic phase at -30 ° C, T _{C is} described as <-20 ° C.

(3) Viscosity (volume viscosity; η; measured at 20 ° C; mPa.s): For measurement, an E-type rotary viscometer manufactured by Tokyo Keiki Co., Ltd. was used.

(4) Viscosity (rotational viscosity; γ1; measured at 25 ° C; mPa.s): According to "Molecular Crystals and Liquid Crystals" by M. Imai et al. No. 259th The measurement is performed by the method described in page 37 (1995). A sample was placed in a TN device having a twist angle of 0 ° and a distance (cell gap) between two glass substrates of 5 μm. A voltage was applied to the element in a range of 16V to 19.5V in steps of 0.5V. 0.2 seconds after no voltage was applied, it was repeatedly applied under the conditions of applying only one rectangular wave (rectangular pulse; 0.2 second) and no voltage (2 seconds). The peak current and peak time of a transient current generated by the application were measured. From these measured values and the calculation formula (8) described on page 40 in the paper by M. Imai et al., The value of the rotational viscosity was obtained. The value of the dielectric anisotropy required for the calculation is obtained by using the device whose rotational viscosity is measured by a method described below.

(5) Optical anisotropy (refractive index anisotropy; Δn; measured at 25 ° C): Measurement was performed using an Abbe refractometer with a polarizing plate attached to an eyepiece using light having a wavelength of 589 nm. After rubbing the surface of the main shaft in one direction, the sample was dropped on the main shaft. The refractive index n 测定 is measured when the direction of polarized light is parallel to the direction of rubbing. The refractive index n 测定 is measured when the direction of polarized light is perpendicular to the direction of rubbing. The value of optical anisotropy is calculated according to the formula of Δn = n ∥-n ⊥.

(6) Dielectric anisotropy (Δε; measured at 25 ° C): In a TN device in which the distance (cell gap) between two glass substrates is 9 μm and the twist angle is 80 degrees Place the sample. A sine wave (10 V, 1 kHz) was applied to the device, and the dielectric constant (ε ∥) of the long axis direction of the liquid crystal molecules was measured 2 seconds later. A sine wave (0.5 V, 1 kHz) was applied to the device, and the dielectric constant (ε ⊥) of the minor axis direction of the liquid crystal molecules was measured after 2 seconds. The value of dielectric anisotropy was calculated according to the formula of Δε = ε ∥-ε ⊥.

(7) Threshold voltage (Vth; measured at 25 ° C; V): The LCD5100 type luminance meter manufactured by Otsuka Electronics Co., Ltd. was used for the measurement. The light source is a halogen lamp. A sample was placed in a normally white mode TN device in which the distance (cell gap) between two glass substrates was 0.45 / Δn (μm) and the twist angle was 80 degrees. The voltage (32 Hz, rectangular wave) applied to the device was increased in steps from 0 V to 10 V in units of 0.02 V. At this time, the device was irradiated with light from the vertical direction, and the amount of light transmitted through the device was measured. A voltage-transmittance curve having a transmittance of 100% when the amount of light reaches the maximum and a transmittance of 0% when the amount of light is the smallest is made. The threshold voltage is expressed by the voltage when the transmittance reaches 90%.

(8) Voltage holding ratio (VHR-1; measured at 25 ° C;%): The TN device used in the measurement had a polyimide alignment film, and the distance (cell gap) between the two glass substrates was 5 μm. After the sample is added, the element is sealed with an adhesive that is hardened with ultraviolet rays. A pulse voltage (5 V, 60 microseconds) was applied to the TN element to charge it. The decaying voltage was measured between 16.7 milliseconds using a high-speed voltmeter, and the area A between the voltage curve and the horizontal axis in a unit cycle was obtained. The area B is the area without attenuation. The voltage holding ratio is expressed as a percentage of the area A to the area B.

(9) Voltage holding ratio (VHR-2; measured at 80 ° C;%): Measured by the same procedure as described above, except that the measurement is performed at 80 ° C instead of 25 ° C. Voltage holding rate. The obtained value is represented by VHR-2.

(10) Voltage holding ratio (VHR-3; measured at 25 ° C;%): After irradiation with ultraviolet rays, the voltage holding ratio was measured to evaluate the stability to ultraviolet rays. The TN device used for the measurement had a polyimide alignment film, and the cell gap was 5 μm. A sample was injected into the device, and the device was irradiated with light for 20 minutes. The light source is an ultra-high pressure mercury lamp USH-500D (made by Ushio Motor), and the distance between the element and the light source is 20 cm. In the measurement of VHR-3, the attenuated voltage was measured between 16.7 milliseconds. A composition having a large VHR-3 has a large stability to ultraviolet rays. VHR-3 is preferably 90% or more, and more preferably 95% or more.

(11) Voltage holding ratio (VHR-4; measured at 25 ° C;%): After heating the TN device filled with the sample in a constant temperature bath at 80 ° C for 500 hours, the voltage holding ratio was measured to evaluate the thermal resistance stability. In the measurement of VHR-4, the attenuated voltage was measured between 16.7 milliseconds. A composition having a large VHR-4 has a large stability to heat.

(12) Response time (τ; measured at 25 ° C; ms): The LCD5100 brightness meter manufactured by Otsuka Electronics Co., Ltd. was used for the measurement. The light source is a halogen lamp. The low-pass filter is set to 5 kHz. A sample was placed in a normally white mode TN device in which the distance (cell gap) between two glass substrates was 5.0 μm and the twist angle was 80 degrees. A rectangular wave (60 Hz, 5 V, 0.5 seconds) was applied to the device. At this time, the device was irradiated with light from the vertical direction, and the amount of light transmitted through the device was measured. When the light amount reaches the maximum, the transmittance is regarded as 100%, and when the light amount is the minimum, the transmittance is regarded as 0%. Rise time (τr: rise time; milliseconds) is Time required for the transmittance to change from 90% to 10%. Fall time (τf: fall time; milliseconds) is the time required for the transmittance to change from 10% to 90%. The response time is represented by the sum of the rise time and the fall time obtained in the manner described above.

(13) Elastic constant (K; measured at 25 ° C; pN): The HP4284A type LCR meter manufactured by Yokogawa-Hewlett-Packard Co., Ltd. was used for the measurement. A sample was placed in a horizontal alignment element having a distance (cell gap) between two glass substrates of 20 μm. A charge of 0 volts to 20 volts was applied to the device, and the capacitance and the applied voltage were measured. Using equations (2.98) and (2.101) on page 75 of the "Liquid Crystal Device Handbook" (Nikkan Kogyo Shimbun), the measured capacitance (C) and the value of the applied voltage (V) are fitted, and the equation ( 2.99) Obtain the values of K11 and K33. Then, in formula (3.18) on page 171 of the "Liquid Crystal Device Handbook", K22 was calculated using the values of K11 and K33 just obtained. The elastic constant is represented by the average value of K11, K22, and K33 calculated | required as mentioned above.

(14) Specific resistance (ρ; measured at 25 ° C; Ωcm): 1.0 mL of a sample was poured into a container provided with an electrode. A DC voltage (10 V) was applied to the container, and a DC current after 10 seconds was measured. The specific resistance is calculated from the following formula. (Specific resistance) = {(voltage) × (capacitance of the container)} / {(DC current) × (dielectric constant of vacuum)}.

(15) Spiral pitch (P; measured at room temperature; μm): The spiral pitch is measured by the wedge method. Refer to "LCD Fact Sheet" on page 196 (issued in 2000, Maruzen). The sample was injected into the wedge-shaped unit and left at room temperature for 2 hours, and then the interval of the disclination line was observed using a polarizing microscope (Nikon (stock), trade name MM40 / 60 series) ( d2-d1). Helix pitch (P) is the root The angle of the wedge element is calculated by the following expression, which is θ. P = 2 × (d2-d1) × tanθ.

(16) Dielectric constant in the minor axis direction (ε ⊥; measured at 25 ° C.): A sample was placed in a TN device in which the distance (cell gap) between two glass substrates was 9 μm and the twist angle was 80 degrees. A sine wave (0.5 V, 1 kHz) was applied to the device, and the dielectric constant (ε ⊥) of the minor axis direction of the liquid crystal molecules was measured after 2 seconds.

The compounds in the examples are represented by symbols based on the definitions in Table 3 below. In Table 3, the stereo configuration related to 1,4-cyclohexyl is a trans configuration. The number in parentheses after the mark corresponds to the number of the compound. The symbol (-) means another liquid crystal compound. The ratio (percentage) of the liquid crystal compound is a weight percentage (% by weight) based on the weight of the liquid crystal composition. Finally, the characteristic values of the composition are summarized.

[Comparative Example 1]

It is selected from the composition disclosed in Japanese Patent Laid-Open No. 10-81679 Example 33. It is believed that this composition contains compounds (1), (3-1), (3-4), (4) and similar compounds of compound (2), and does not contain a cyano compound. The components and characteristics of the composition are as follows.

NI = 86.5 ℃; △ n = 0.099; △ ε = 5.3; Vth = 2.18V; η = 23.5mPa. s.

[Example 1]

A compound similar to the compound (2) contained in the composition of Comparative Example 1 was replaced with the compound (2) to prepare a composition of the present application. The components and characteristics of the composition are as follows.

NI = 85.7 ℃; △ n = 0.099; △ ε = 5.2; Vth = 2.17V; η = 22.4mPa. s.

[Example 2]

NI = 86.7 ℃; Tc <-20 ℃; Δn = 0.121; Δε = 2.7; Vth = 2.76V; η = 13.5mPa. s; γ1 = 75.8mPa. s; ε ⊥ / △ ε = 1.33.

[Example 3]

NI = 86.5 ℃; Tc <-20 ℃; △ n = 0.094; △ ε = 8.0; Vth = 1.53V; η = 16.5mPa. s; γ1 = 92.4mPa. s.

[Example 4]

NI = 81.2 ℃; Tc <-20 ℃; △ n = 0.114; △ ε = 2.9; Vth = 2.72V; η = 13.3mPa. s; γ1 = 75.1mPa. s; ε ⊥ / △ ε = 1.20.

[Example 5]

NI = 101.9 ℃; Tc <-20 ℃; Δn = 0.116; Δε = 5.4; Vth = 1.83V; η = 22.6mPa. s.

[Example 6]

NI = 102.9 ℃; Tc <-20 ℃; Δn = 0.107; Δε = 6.1; Vth = 1.78V; η = 22.7mPa. s.

[Example 7]

NI = 93.5 ℃; Tc <-20 ℃; △ n = 0.108; △ ε = 5.4; Vth = 1.88V; η = 14.8 mPa. s; γ1 = 82.9mPa. s; ε ⊥ / △ ε = 0.68.

[Example 8]

NI = 82.3 ℃; Tc <-20 ℃; △ n = 0.099; △ ε = 4.3; Vth = 1.96V; η = 12.3 mPa. s; γ1 = 68.9mPa. s.

[Example 9]

NI = 92.5 ℃; Tc <-20 ℃; △ n = 0.127; △ ε = 5.7; Vth = 1.83V; η = 15.8mPa. s; γ1 = 88.5mPa. s; ε ⊥ / △ ε = 0.63.

[Example 10]

NI = 92.3 ℃; Tc <-20 ℃; △ n = 0.115; △ ε = 4.0; Vth = 2.28V; η = 16.4mPa. s; γ1 = 91.8mPa. s.

[Example 11]

NI = 97.6 ℃; Tc <-20 ℃; △ n = 0.089; △ ε = 2.9; Vth = 2.73V; η = 19.2mPa. s.

[Example 12]

NI = 88.6 ℃; Tc <-20 ℃; △ n = 0.095; △ ε = 4.4; Vth = 1.95V; η = 11.4mPa. s; γ1 = 63.8mPa. s.

[Example 13]

NI = 85.1 ℃; Tc <-20 ℃; △ n = 0.099; △ ε = 6.7; Vth = 1.70V; η = 16.5mPa. s.

[Example 14]

NI = 78.9 ℃; Tc <-20 ℃; △ n = 0.119; △ ε = 6.9; Vth = 1.68V; η = 17.5mPa. s.

[Example 15]

NI = 85.6 ℃; Tc <-20 ℃; △ n = 0.121; △ ε = 5.7; Vth = 1.85V; η = 13.2mPa. s; γ1 = 73.9mPa. s; ε⊥ / △ ε = 0.65.

The viscosity (η) of the composition of Comparative Example 1 was 23.5. On the other hand, the viscosity of the composition of Example 1 was 22.4. As such, the composition containing the compound (2) example has a smaller viscosity than the composition of the comparative example. Therefore, it was concluded that the liquid crystal composition of the present invention has excellent characteristics.

[Industrial availability]

The liquid crystal composition of the present invention has a high upper limit temperature, a low lower limit temperature, a small viscosity, an appropriate optical anisotropy, a large dielectric anisotropy, a large specific resistance, a high stability to ultraviolet rays, and a high resistance to heat. Among the characteristics such as high stability, large elastic constant, etc., at least one characteristic is satisfied, or at least two characteristics are appropriately balanced. The liquid crystal display element containing the composition has a short response time, a large voltage holding ratio, a large contrast ratio, a long life, and the like, and thus can be used for a liquid crystal projector, a liquid crystal television, and the like.

Claims (20)

A liquid crystal composition containing at least one compound selected from the group of compounds represented by formula (1) as a first component and at least one compound selected from the group of compounds represented by formula (2) The compound is the second component and has a nematic phase,

In formula (1) and formula (2), R ¹ is a C 1-12 alkyl group, a C 1-12 alkoxy group, or a C 2-12 alkenyl group; R ² is a C 1 to Alkyl group of 3 or at least one hydrogen is substituted with halogen and a C1-C12 alkyl group; R ³ is hydrogen or C1-C5 alkyl group; Ring A and Ring B are independently 1,4-extended Cyclohexyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4-ethylene Phenyl, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5-diyl; Z ¹ and Z ^{2 are} independently single bonds , Ethylidene, vinylidene, methyleneoxy or carbonyloxy; X ¹ is hydrogen or fluorine; Y ¹ is fluorine; j and k are independently 0, 1, 2 or 3; and j and k The sum is 4 or less. The liquid crystal composition according to item 1 of the patent application scope, which contains a compound selected from the compounds represented by formula (1-1) to formula (1-3), formula (1-5) to formula (1-7) At least one compound in the group as the first component,

In formula (1-1) to formula (1-3), formula (1-5) to formula (1-7), R ¹ is a C 1-12 alkyl group, a C 1-12 alkoxy group Or an alkenyl group having 2 to 12 carbon atoms; X ¹ , X ² , X ³ , X ⁴ , X ⁵ , X ⁶ and X ^{7 are} independently hydrogen or fluorine; Y ¹ is fluorine. The liquid crystal composition according to item 1 of the patent application range, wherein the proportion of the first component is in the range of 5 to 40% by weight, and the proportion of the second component is 10 to 60% by weight based on the weight of the liquid crystal composition % Range. The liquid crystal composition according to item 1 of the patent application scope further contains at least one compound selected from the group of compounds represented by formula (3) as the third component,

In formula (3), R ⁴ and R ^{5 are} independently C 1-12 alkyl, C 1-12 alkoxy, C 2-12 alkenyl, and at least one hydrogen is substituted with halogen Alkyl having 1 to 12 carbons, or alkenyl having 2 to 12 carbons in which at least one hydrogen is substituted with fluorine; ring C and ring D are independently 1,4-cyclohexyl, 1,4-extend Phenyl, 2-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene; Z ³ is a single bond, ethyl ester, or carbonyloxy; n is 1, 2 Or 3; here, when n is 1, ring D is 1,4-phenylene. The liquid crystal composition according to item 1 of the patent application scope, which contains at least one compound selected from the group of compounds represented by formula (3-1) to formula (3-12) as a third component,

In formula (3-1) to formula (3-12), R ⁴ and R ^{5 are} independently an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, and an alkenyl group having 2 to 12 carbons Or at least one hydrogen-substituted alkenyl group having 2 to 12 carbon atoms. The liquid crystal composition as described in item 4 of the patent application range, wherein the proportion of the third component is in the range of 5 to 55% by weight based on the weight of the liquid crystal composition. The liquid crystal composition according to item 1 of the patent application scope, which further contains at least one compound selected from the group of compounds represented by formula (4) as the fourth component,

In formula (4), R ⁶ is an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, or an alkenyl group having 2 to 12 carbons; ring E is 1,4-cyclohexyl, 1 , 4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyrimidine -2,5-diyl, or tetrahydropyran-2,5-diyl; Z ⁴ is a single bond, ethylidene, carbonyloxy, or difluoromethyleneoxy; X ⁸ and X ^{9 are} independent The ground is hydrogen or fluorine; Y ² is fluorine, chlorine, at least one hydrogen is substituted with halogen and a C 1-12 alkyl group, at least one hydrogen is substituted with halogen and a C 1-12 alkoxy group, Or at least one hydrogen-substituted alkenyloxy group having 2 to 12 carbon atoms with halogen; p is 1, 2, 3, or 4. The liquid crystal composition according to item 4 of the patent application scope further contains at least one compound selected from the group of compounds represented by formula (4) as the fourth component,

In formula (4), R ⁶ is an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, or an alkenyl group having 2 to 12 carbons; ring E is 1,4-cyclohexyl, 1 , 4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyrimidine -2,5-diyl, or tetrahydropyran-2,5-diyl; Z ⁴ is a single bond, ethylidene, carbonyloxy, or difluoromethyleneoxy; X ⁸ and X ^{9 are} independent The ground is hydrogen or fluorine; Y ² is fluorine, chlorine, at least one hydrogen is substituted with halogen and a C 1-12 alkyl group, at least one hydrogen is substituted with halogen and a C 1-12 alkoxy group, Or at least one hydrogen-substituted alkenyloxy group having 2 to 12 carbon atoms with halogen; p is 1, 2, 3, or 4. The liquid crystal composition according to item 1 of the patent application scope, which contains at least one compound selected from the group of compounds represented by formula (4-1) to formula (4-24) as the fourth component,

In formula (4-1) to formula (4-24), R ⁶ is an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, or an alkenyl group having 2 to 12 carbons. The liquid crystal composition according to item 4 of the patent application scope, which contains at least one compound selected from the group of compounds represented by formula (4-1) to formula (4-24) as the fourth component,

In formula (4-1) to formula (4-24), R ⁶ is an alkyl group having 1 to 12 carbons, an alkoxy group having 1 to 12 carbons, or an alkenyl group having 2 to 12 carbons. The liquid crystal composition as described in item 7 of the patent application range, wherein the proportion of the fourth component is in the range of 5 to 35% by weight based on the weight of the liquid crystal composition. The liquid crystal composition according to item 1 of the patent application scope, which contains at least one compound selected from the group of compounds represented by formula (5) as the fifth component,

In formula (5), R ⁷ and R ^{8 are} independently C 1-12 alkyl, C 1-12 alkoxy, C 2-12 alkenyl, C 2-12 alkenyl Group, or an alkyl group having 1 to 12 carbons in which at least one hydrogen is substituted with halogen; ring F and ring I are independently 1,4-cyclohexyl, 1,4-cyclohexenyl, 1,4 -Phenylene, 1,4-phenylene substituted with at least one hydrogen by fluorine or chlorine, or tetrahydropyran-2,5-diyl; ring G is 2,3-difluoro-1,4 -Phenylene, 2-chloro-3-fluoro-1,4-phenylene, 2,3-difluoro-5-methyl-1,4-phenylene, 3,4,5-trifluoronaphthalene -2,6-diyl, or 7,8-difluorochroman-2,6-diyl; Z ⁵ and Z ^{6 are} independently a single bond, ethylidene, carbonyloxy, or methyleneoxy Base; e is 1, 2 or 3, f is 0 or 1; and the sum of e and f is 3 or less. The liquid crystal composition according to item 8 of the patent application scope, which contains at least one compound selected from the group of compounds represented by formula (5) as the fifth component,

In formula (5), R ⁷ and R ^{8 are} independently C 1-12 alkyl, C 1-12 alkoxy, C 2-12 alkenyl, C 2-12 alkenyl Group, or an alkyl group having 1 to 12 carbons in which at least one hydrogen is substituted with halogen; ring F and ring I are independently 1,4-cyclohexyl, 1,4-cyclohexenyl, 1,4 -Phenylene, 1,4-phenylene substituted with at least one hydrogen by fluorine or chlorine, or tetrahydropyran-2,5-diyl; ring G is 2,3-difluoro-1,4 -Phenylene, 2-chloro-3-fluoro-1,4-phenylene, 2,3-difluoro-5-methyl-1,4-phenylene, 3,4,5-trifluoronaphthalene -2,6-diyl, or 7,8-difluorochroman-2,6-diyl; Z ⁵ and Z ^{6 are} independently a single bond, ethylidene, carbonyloxy, or methyleneoxy Base; e is 1, 2 or 3, f is 0 or 1; and the sum of e and f is 3 or less. The liquid crystal composition according to item 1 of the patent application scope, which contains at least one compound selected from the group of compounds represented by formula (5-1) to formula (5-19) as a fifth component,

In formula (5-1) to formula (5-19), R ⁷ and R ^{8 are} independently C 1-12 alkyl, C 1-12 alkoxy, C 2-12 alkenyl , An alkenyloxy group having 2 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted with halogen. The liquid crystal composition according to item 8 of the patent application range, which contains at least one compound selected from the group of compounds represented by formula (5-1) to formula (5-19) as the fifth component,

In formula (5-1) to formula (5-19), R ⁷ and R ^{8 are} independently C 1-12 alkyl, C 1-12 alkoxy, C 2-12 alkenyl , An alkenyloxy group having 2 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted with halogen. The liquid crystal composition as described in item 12 of the patent application range, wherein the proportion of the fifth component is in the range of 3% to 25% by weight based on the weight of the liquid crystal composition. The liquid crystal composition as described in item 1 of the patent application, the upper limit temperature of the nematic phase is 70 ° C or more, the optical anisotropy (measured at 25 ° C) at a wavelength of 589 nm is 0.07 or more, and the frequency at 1 kHz The dielectric anisotropy (measured at 25 ° C) is 2 or more. A liquid crystal display element containing the liquid crystal composition as described in item 1 of the patent application. The liquid crystal display element of claim 18, wherein the operation mode of the liquid crystal display element is twisted nematic mode, electronically controlled birefringence mode, optically compensated bending mode, in-plane switching mode, fringe field switching mode, or electric field In response to the light alignment mode, the driving method of the liquid crystal display element is an active matrix method. A use of the liquid crystal composition as described in item 1 of the patent application scope in a liquid crystal display element.